Parks Canada marcus waring, Parks Canada

Waterton Lakes National Park Avalanche Forecast

Dec 30th, 2019 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Deep Persistent Slabs and Wind Slabs.

Snow from last weeks storm is settling well but the variable sensitivity of a weak facet/crust combo at the base of snowpack requires a cautions approach to terrain. 

Summary

Weather Forecast

Tuesday- . Increasing cloud cover through the day with scattered flurries. West wind 50km/h gusting to 80 km/h. Freezing level 1200m.

Tuesday Night- Expecting 2-5 mm of precip by Wed AM.

Wednesday- A mix of sun and cloud with Strong - Moderate wind. Isolated flurries. Freezing Level 1400m

Thursday- A mix of Sun and cloud with a chance of flurries.

Snowpack Summary

Strong Westerly winds continue to develop Windslab at treeline & above. A deteriorating melt freeze crust exists on all aspects up to 1800m. Above 1800m, 85-120cm of well settled snow from last weeks storm sits on top of a weak facet/ melt freeze crust near the base of the snowpack. Reactivity of this basal weakness is variable & warrants caution.

Avalanche Summary

No new activity last 3 days.

Confidence

Forecast snowfall amounts are uncertain on Tuesday

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Likelihood

Possible - Unlikely

Expected Size

2 - 3

The November facet/ melt freeze crust combo still lurks near the base of the snowpack. This layer could still be triggered by people in thinner snowpack areas, or by large triggers including cornices or smaller avalanches.

  • Use conservative route selection, choose moderate angled and supported terrain with low consequence.
  • Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

Wind slabs will be thicker and more reactive the higher you go.

  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
  • Use caution in lee areas in the alpine and treeline. Recent storm snow has formed wind slabs.

Aspects:

North, North East, East, South East, South.

Elevations:

Alpine, Treeline.

Valid until: Jan 2nd, 2020 4:00PM